Haywaed augustus habvey



(No Model.)

H. A. HARVEY. ROLLED HE ADED WOOD SCREW AND PROCESS OF MAKING THE SAME.

No.' 37'7,453. Patented Feb. 7, 1888.

, V UNIT STATES PATENT OFFICE.

HAYWARDAUGUSTUS HARVEY, OF QRANGE, NEWJnRsEY.

ROLLED-HEADED WOODSCREW AND PROCESS OF MAKING THE SAME.

.EPECIFICATION forming part of Letters Patent No. 377,453, dated February 7,

Application filed September 19, 1887. Serial No. 250,125. (No model.)

away with the operation of shaving the heads of the ordinary flat-headed wood-screws, and to give to such heads the advantageous qualities which they acquire by being rolled. The effect of rolling is to so condense andstiffen the metal of which the heads are composed that they are given greatly-increased capacity of resisting any tendency to split along the lineof the,

nick when the screw is being driven or forced into the object into which it is intended to be inserted.

The invention consists in finishing and shaping the head of a headed wood-screw blank by rolling such head between dies, each of which is provided with a ratchet-shaped groove, the walls of which groove are intended to bear,respectively, upon the top and upon the under side of thehead of the blank,the wallintended to bear upon the topbeing less nearly perpendicular to the axial line of the blank than the top of the head of the, blank is, and the wall intended to bear upon the under side being more nearly perpendicular to the axial line of the blank than the under side of the blank is.

The accompanying drawings illustrate a form of dieswhich are included in the present invention, and which are adapted for rolling the heads of ordinary flat-head screws.

The drawings are as follows: Figure l is an axial section of the head and adjoining portion of the body of a flat-headed screw-blank and atransverse section of apair of dies for rolling such head, showing the diesin the relative positions which they occupy at the instant of their first engagement with the head.-that is, at the commencementof the rolling operation.

Fig.2 is a drawing similar to Fig. 1, except that it represents a later stage in the rolling operation. Fig. 3 is a drawing similar to Figs. 1 and 2, but representing the concluding stage in the rolling operation.

. For olearness of illustration. the drawings are purposely made on a magnified scale.

The dies Au may in the direction of the I length be either straightor curved, andniay 1 be moved relatively in opposite directions; or

one die may beheld stationary while they other y is moved to perform the rolling operation,dur-

ing the performance of whichthe space be the dies is apfor operating the dies, because such mechan isms are well known, having been fully'shown and described inLetters Patent of the-United States, Nos. 223,730 and-357,001, dated, re-Z; V

spectively, January 20, 188i), and February 1, 1887, granted to. H. A. Harvey for improve wood-screws.

-ments in machines for rolling'the threads of; 7

The characteristic feature of the dies A a is the shape in cross-section of the longitudinal grooves A a, with which they are respectively provided lt will beseen, upon comparing these grooves with the shape in axial section of the head B of the headed blank shown in Fig. 1, that the walls A a ofthe grooves, respectively, which bear upon the top b of thehead areso inclined'as to make slightly-obtuse angles with the parallel faces of the dies, and are hence inclined'toward the head from a line perpendicular to the axial that the opposite walls, A a, of the grooves, respectively, are less inclined from a line 'perpendicular to the axial line of the blank than the under side of the head is. Itresults from this contour of the grooves inv cross-section that when the dies first engage the head they bear upon the outer'edge of thetop of the head and upon a point near the body upon the under side of the head. As the rollingoperation proceeds,the outer portionof the head is bent toward the body of the blank, as illustrated in an extravagant way in Fig. 2. When the operation of rolling is concluded, the head is so far set back that'it completelyfills the grooves, as illustrated in Fig.3, in which, as will be seen,th'e top of the head is very slightly conical or full in the-center.

It willof course be perceived that the top of the head when finished willhaveacqui-redthe shape in reverse of the'walls A? a of (the grooves, and that the top of the head when s'e line of the screw-blank. It will also be seen finished can be made either more or less conical or more or less spheroidal by suitably varying the contour in crosssection of the walls A a of the grooves. l

The grooves A or, adapted to bear initially upon the exterior portion of the top of the head and upon a part of the under side of the head near the body, are especially suitable for rolling the heads of ordinary flat-headed screws. Doubtless other forms of grooves may be usefully employed for the same pur- Screw-blanks which have been headed in,

solid dies in the ordinary double-blow header may have their heads perfectly finished by the herein-described process of rolling,so that the ordinary process of shaving the heads can be dispensed with. It will of course be seen that the heads of shaved blanks may also be rolled, 0

as herein described, and will thereby be rendered more capable of resisting strains tending to split them, as herein set forth.

What is claimed as the invention is- 1. As a new article of manufacture,a woodscrew provided with a rolled head the top of which is slightly conical or conoidal, substantially as described.

2. For employment in rolling the heads of flat-headed blanks or screws, finishing and 40 shaping dies, each of which is provided with a ratchet-shaped groove, one wall of which groove is less nearly perpendicular to the axial line of the blank than is the top of the headed blank upon which itisintended to bear,

and the other wall of which is more nearly perpendicular to the axial line of the blank than the under side of the head of the blank upon which it is intended to bear,whereby the initial bearing-points of the dies upon the head upon which they act are respectively upon the outer portions of the top of the head and upon portions of the under side of the head near the body, substantially as set forth.

HAYWARD AUGUSTUS HARVEY. YVitnesses:

L. L. FARR, A. M. JoNEs. 

